Mechanism for driving rotary kilns

ABSTRACT

A MECHANISM FOR DRIVING AN OPEN-ENDED ROTARY KILN OR GRINDER CARRIES A DRIVE GEAR WHICH MESHES WITH A DRIVING PINION. THE LATTER IS IN TURN DRIVEN BY AN OUTPUT SHAFT OF A SECOND OF TWO PLANETARY GEAR TRAINS. THE GEAR TRAINS ARE COUPLED THROUGH THE PLANET CARRIER OF THE FIRST AND THE DRIVE GEAR OF THE SECOND. THE GEAT TRAINS ARE MOUNTED ON ONE EITHER SIDE OF THE DRIVING PINION.

United States Patent [56] References Cited UNITED STATES PATENTS 4/1952 Ridgely [72] Inventor Georges Henriot llnuilles, France [21] Appl. No. 810,509

2,591,967 ggf nf 2 3'}??? 2,844,052 7/1958 Stoekicht.......... [73] Assignee Engrenageset-Reducwurs 3,146,629 9/1964 Schmitter.....................

(Engrenages Citroen et E1 Robe t Me i Primary Examiner-Leonard H. Gerin Keunis), Paris, France Attomey-Steinberg & Blake 32 I'r iority Mar. 27, 1968,51, 31, 1968 France 145,722 and 182,547

ABSTRACT: A mechanism for driving an open-ended rotary kiln or grinder carries a drive gear which meshes with a driving [54] MECHANISMS FOR DRIVING ROTARY KILNS 9 Claims, 7 Drawing Figs.

pinion. The latter is in turn driven by an output shaft of a second of two planetary gear trains. The gear trains are con- 74/410 F1611 57/00 pled through the planet carrier of the first and the drive gear 74/410, of the second. The gear trains are mounted one one either side 801, 750 of the driving pinion.

[51] Int. [50] Field of PATENTED JUN28 |97l 3 587' 3 38 SHEET 2 OF 4 Inventor (mm m M707 A llorm'yg PATENTEB JUH28 1971 SHEET 3 [IF 4 W mm H mm m. x mm mm, hm mm NW vm ww mm w/ Z/ TX 1 1 hm mm w w I n y V%% v \M. mw W w 2 Y V! mw 5mm A Home y 5 MECHANISMS FOR DRIVING ROTARY KILNS BACKGROUND OF THE INVENTION 1. Field of the invention This invention relates to a mechanism for imparting to a body of large mass, such as a grinding mill, a cement works kiln or the like, rotary motion about its own axis.

2. Description of the Prior Art There are well-known mechanisms capable of imparting rotary motion to one end of a body of large mass, such as a hollow container filled with material for processing therein, while leaving unobstructed the end thus driven.

Examples of such mechanisms are used for driving certain grinders and cement kilns, consisting of a toothed ring (gear ring) fixed to the body that is to be driven, the longitudinal centerline of which coincides with its axis of rotation. One or more pinion wheels, each driven through reduction gearing by a motor, mesh with the toothed ring, to which rotary motion is thus imparted. The toothed ring and pinions are generally enclosed in a casing.

Such a mechanism enables raw material to be loaded and processed material to be removed through the end by which the hollow container is driven. These operations can be carried out continuously, if required, and in any case without the rotation of the container having to be stopped.

Previously proposed mechanisms have certain drawbacks, however, among which mention may be made of their high cost of production and the large amount of space occupied by each of the units concerned (motor, resilient couplings and reduction gearing).

An object of the present invention is to at least partially overcome the disadvantages.

SUMMARY OF THE INVENTION According to the present invention there is provided a mechanism for imparting rotary motion to a grinder, a cement kiln or other hollow body, comprising at least one speedreducing gear driven by a motor, said speed-reducing gear including two planetary gear trains, the planet-wheel carrier of the first train being connected to the sun gear of the second train so as to rotate with it, the hollow body being provided with an axial opening, at the outer periphery of which is fitted a drive gear coaxial with that opening, the drive gear operating in conjunction with at least one pinion with a central opening and keyed to the output shaft of the speed-reducing gear, the first and second planetary gear trains being disposed on opposite sides of the pinion and one member of one of the trains being connected to one member of the other train by a spindle passing through the opening of the pinion.

In a preferred embodiment, the planet wheel carrier of the second planetary train is connected so as to rotate with the pinion that drives the drive gear.

It is also desirable for the annulus gears of the two planetary trains to be rigidly connected to the support of the bearings in which the pinions rotate.

Finally, in one simple embodiment, the motor driving each reducing gear train is rigidly mounted on the substructure and connected to the reduction gear input shaft by a resilient coupling.

In addition, it is necessary for the support carrying the bearings in which the pinions rotate to be satisfactorily guided axially and radially and hence properly centered in relation to the opening in the hollow body.

For this purpose, a number of rolling and guiding components are disposed between, on the one hand, the end, preferably double walled, of the hollow body, fixed to the drive gear, and/or the drive gear, and, on the other hand, the support carrying the bearings in which the pinions rotate.

As regards the radial guidance, the rolling and guiding components consist of self-aligning roller bearings disposed in pairs, the bearings in one pair being preferably disposed in a single plane passing through the axis of the opening in the hollow body, there being preferably four pairs of bearings mounted at the corners of a square.

LII

For axial guidance, each rolling and guiding component consists of an external race, of torus section, the axis of the ring being perpendicular to the axis of the opening in the hollow body. In one particular form of construction, the ring may bear on a shoulder rigidly attached to the opening in the hollow body provided with the drive gear, this shoulder consisting preferably of the drive gear itself. For certain purposes more than two planetary gear trains may be employed.

By making use of a mechanism in accordance with the invention, it is possible to dispense with any resilient coupling between the reduction gear and pinion. Moreover, the masses and spaces making up each reduction gear will be advantageously distributed on both sides of the pinion.

These arrangements result in an appreciable reduction in resonance effects and a modification in critical speeds.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is an axial section of a grinder driven by mechanism in accordance with the invention;

FIG. 2 shows, in outline, the driving arrangements, as seen by an observer looking in the direction of the arrow F in FIG.

FIG. 3 is a section on the line III-III of FIG. 2;

FIG. 4 is a section of part of a grinder equipped with mechanism in accordance with the invention;

FIG. 5 is a partial perspective view of a grinder equipped with mechanism in accordance with the invention; and

FIGS. 6 and 7 are sections showing bearing and guidance component assemblies. The description and drawings are given, of course, by way of example only, no limitation on the scope of the invention being thereby implied.

The equipment includes a cylindrical hollow body I, which contains material 2. It is supported at one end and is driven at one of its axial ends, for which purpose a drive gear 4 is fast with that end, which, in this embodiment, is supported by the bearing 3.

The pinions 5 mesh with the drive gear 4 but are supported by structure 6, centered on the axis of rotation of the body and usually serving additionally as a casing to protect the drive gear and pinions.

An essential element in the functioning of the equipment as a whole, although a secondary importance as regards the invention, is a torque-absorption device consisting of reaction rods 7, cylinders 9, springs 10 and stops 8. The cylinders 9 are secured to the floor 11, the stops 8 being secured within their upper ends.

FIG. 3 shows diagrammatically various parts of a reduction gear driving one pinion. The driving motor 12 has output shaft 140, and a resilient or splined coupling 13 connects the motor output shaft 14a to the reduction gear input shaft 14b.

The reduction gear, in the preferred embodiment, includes two planetary gear trains l5 and 16, disposed respectively on opposite sides of the casing 6.

The shaft 14b is rigid with the sun gear I7 of the first train, while the planet carrier 18 of the first train and the sun gear 21 of the second train are coupled, so as to rotate together, by a spindle 25. It will be observed that the spindle 25 passes through the pinion 5, which is made hollow for that purpose.

Finally, the planet carrier 22 of the second train 16 is fast with the pinion 5, while the two annulus or ring gears 20 and 24 are fast with the casing 6. The numerals I9 and 23 designate one of the planet wheels in the first and second planetary trains respectively.

Shown in the form of a half section in FIG. 4 is one end portion 26, of the grinder, to which the toothed ring gear 4 is fixed. If the grinder is likely to contain materials heated to high temperatures, the end portion 26 should have a double wall 26a and 26b, spaced apart and stiffened by intermediate members 27. This end portion 26 may be in the form of a single casting. The drive gear 4, of welded construction, is fixed to the end portion 26 by welds 40, by which the drive gear is secured to the outer end wall 26a. The provision of the walls 26a and 26b enables a cooling fluid to be circulated, which reduces deterioration of the equipment in the course of operation and, of course, reduces the temperature of the walls, especially of the outer wall 26a.

The structure 6 must be centered both radially and axially in relation to the end portion 26.

Radially, the structure 6 is held by bearings 28, of self-aligning roller type in the example illustrated. Each bearing is positioned opposite one of the intermediate members 27 which also acts as a stiffener. The spindle 29 of each bearing 28 is rigid with the structure 6, and the outer race 30 of the bearing bears against the wall 2611. Two seals 31, are fitted between the wall 26a and end portion of the structure 6.

As shown in FIG. 5, the bearings 28 are arranged preferably in pairs, the two bearings in each pair being preferably situated in one and the same plane passing through the axis of the end portion 26 of the hollow body. In the form of construction adopted, the bearings of any one pair lie in a line parallel to the axis 32 of the end portion 26; and the axes of the various pairs of bearings 28 in a section taken parallel to the axis 32 are four in number and are situated at the corners of a square.

As regards axial guidance, the structure 6 bears against a shoulder integral with the end portion 26, or against the toothed drive gear 4 itself, through the intermediary of bearings 33. There is no need to elaborate on the mounting of such bearings, which is effected in the conventional way, adjustment being obtained by the insertion of shims 34.

In FIG. 4 a bearing 33 can be seen having its spindle 35 fixed to the structure 6 and its outer race 36 in contact with the drive gear 4. To limit the axial movement of the structure 6 in both directions, in relation to the drive gear 4, it is naturally advisable to provide bearings 33 on each side of the ring 4 i.e. equally spaced around the drive gear.

The shape of the inner race 36 should also be noted, with particular reference to the fact that the face of this component bearing against the drive gear 4, resembles that of a torus. In a midplane section of the bearing, this face appears as an arc of a circle. It will be observed that the spindle 35 of the bearing 33 (which is also the axis of the said race) is perpendicular to the axis 32 of the end portion 26.

Finally, FlGS. 6 and 7 show modifications, in accordance with the invention, in which the bearings 33 bear against a shoulder 37, integral with the end portion 26. This arrangement has the advantage of grouping together the bearings 28 and 33, as well as of making these bearings readily accessible.

The mode of operation of the mechanism as a whole is as follows:

The motor 12, driving through the shafts 14a and 14b and the coupling 13, drives the sun gear 17 of the first train. The sun gear 17 drives the planet wheels 19, which mesh with the teeth on the annulus gear 20, which is stationary in relation to the casing and hence substantially motionless with respect to the ground, and in turn drives the planet wheel carrier 18. The reason for annulus gear being substantially motionless will be apparent from the description given hereinafter. The planet wheel carrier 18 drives the sun gear 21 directly, being rigidly connected to it by the spindle 25. The sun gear 21 drives the planet wheels 23, which, meshing with the teeth on the annulus or ring gear 24, which is substantially motionless with respect to the ground, in turn drives its planet wheel carrier 22. This planet wheel carrier, being fixed so as to rotate with the pinion 5, drives through that pinion the drive gear 4 and hence also the grinder.

As stated above, the members fixed to the casing, the annulus gears of both planetary gear trains and the pinion bearings, are substantially motionless with respect to the ground.

The fact is that when the body is biased to be carried in one direction, the casing, were it notto all intents and purposes keyed to the floor, would rotate about the body, instead of the body rotating in relation to the floor. It is therefore necessary to limit the rotation of the casing when the driving torque supplied by the motors is applied. The reaction rods 7 serve this purpose. When the torque is applied in one direction, one of these rods compresses the corresponding spring 10. When the torque is reversed, the other rod comes into action;

The rods have a secondary function, which may be mentioned here. By appropriate positioning of the rods, the bearing 3 can be relieved of a proportion of the stresses to which it is subjected and can consequently use a bearing of smaller size.

Finally, to allow the casing to oscillate, the shaft 14!; may advantageously be made in the formof two telescopic splined shafts.

The centring of the structure 6 both axially and radially leads to the correct functioning of the various meshing components, especially of the driving pinions acting on the drive gear 4.

The end portion 26 being cooled, thermal expansion in the vicinity of the bearings 28 is moderated, even when the grinder is charged with material at a high temperature. These bearings 28 can therefore be mounted with little play, which is always an advantage for accurate guidance. There is substantially no risk of these bearings 28 becoming overtight and hence wearing prematurely. Since they bear, through the races 30, against a rigid portion of the wall 26a, reinforced by the members 27, their operating conditions are good.

Axial guidance is provided by the bearings 33. The torusshaped races result in practically point-to-point contact with the drive gear 4 or the shoulder 37. This is important in lengthening the life of the bearings 33, especially of the race 36. In particular, this shape eliminates the differences in sliding speed arising over the width of the race when this is externally cylindrical, such differences being the cause of abnormal wear on the conventional cylindrical type.

The improvement in guidance obtainable by the use of the mechanisms here proposed, as compared to that obtainable hitherto, will readily be appreciated. Previously, such devices have required considerable play in assembly and produced undesirable hammering and shaky bearings. It will also be noted that the arrangement shown in H0. 5, in conjunction with the recommended arrangement of the rods 7, makes it possible to bear on only two pairs of bearings 28 simultaneously, the upper or the lower bearings. I

Another important operating feature of the embodiments described is that the driving mechanism as a whole, just described, leaves available, for charging and discharging the material, the end to which the drive is applied.

The invention is naturally not limited to the specific form described above. On the contrary, it includes all such modifications thereof as can be introduced without departing from the scope of the invention as set forth in the appended claims.

lclaim:

1. In a mechanism for rotating a hollow body about the longitudinal axis thereof, said hollow body having an opening coaxial with the axis,

power source means,

speed-reducing means coupled to the power source means,

and including an output shaft a first planetary gear train having a sun gear a plurality of planet wheels, a planet carrier, and an annulus gear, and a second planetary gear train having a sun gear, a plurality of planet wheels, a planet carrier, and an annulus gear, the planet carrier of the first planetary gear being coupled to the sun gear of the second planetary gear train, a drive gear fast for rotation with the hollow body and coaxial with the opening thereof, 1

a pinion having an opening thereinykeyed to the output shaft of the speed-reducing means, and meshing with the drive gear, and

an elongate member passing through the opening in the pinion and coupling a component of the first planetary gear train with a component of the second planetary gear train,

said first and second planetary gear trains being disposed on opposite sides of the said pinion keyed to the output shaft.

2. A mechanism according to claim 1, in which the planet wheel carrier of the second planetary train is coupled to the pinion that drives the drive gear.

3. A mechanism according the claim 1 comprising,

a bearing supporting the pinion and a bearing supporting structure,

the annulus gears of the planetary gear trains being fast with the bearing support structure.

4. A mechanism according to claim 1,

comprising a base structure,

said motor being rigidly mounted on the base structure, and

a resilient coupling connecting the motor and the reducing gear means.

5. A mechanism according to claim 1 comprising,

a plurality of rolling and guiding components,

and end portion of the hollow body,

a bearing of the gear wheel keyed to the output shaft, and

a bearing mounting structure of said bearing,

said rolling and guiding components being interposed between said mounting structure and said end portion.

6. A mechanism according to claim 5, wherein the end portion is double walled.

7. A mechanism according the claim 6, in which the rolling and guiding components consist of self-aligning roller bearings disposed in pairs,

the bearings in one pair being disposed in a single plane passing through the axis of the opening in the hollow body.

8. A mechanism according to claim 5, in which each rolling and guiding component has an external race of torus shape in section, the axis of the race being perpendicular to the axis of the opening in the hollow body.

9. A mechanism according to claim 8, in which races of the rolling and guiding components bear against a shoulder rigidly secured to the end portion of the hollow body, said shoulder being provided by the drive gear. 

